Methods and apparatus for reducing load in a rotor blade

Abstract

A blade includes a plurality of first fibers, wherein each of the plurality of first fibers is angled between about 5° and about 35° with respect to a pitch axis of the blade, and a plurality of second fibers, wherein each of the plurality of second fibers is angled between about 95° and about 125° with respect to the pitch axis of the blade.

1. A blade comprising:
 a plurality of first fibers, wherein each of said plurality of first fibers is angled between 5° and 35° with respect to a pitch axis of said blade; and 
 a plurality of second fibers, wherein each of said plurality of second fibers is angled between 95° and 125° with respect to the pitch axis of said blade, wherein said plurality of first fibers is heavier than said plurality of second fibers, and wherein said plurality of first fibers and said plurality of second fibers are disposed to facilitate a twist of said blade about the pitch axis in response to an aerodynamic bending load on said blade. 
 
   
   
     2. A blade in accordance with  claim 1  wherein each of said plurality of first fibers is angled between 15° and 25° with respect to the pitch axis of said blade, and each of said plurality of second fibers is angled between 105° and 115° with respect to the pitch axis of said blade. 
   
   
     3. A blade in accordance with  claim 1  wherein said plurality of first fibers comprise at least one of glass fibers and carbon fibers. 
   
   
     4. A blade in accordance with  claim 1  wherein said plurality of second fibers comprise at least one of glass fibers and carbon fibers. 
   
   
     5. A blade in accordance with  claim 1  wherein the twist is between 2° and 15°. 
   
   
     6. A blade in accordance with  claim 1  wherein said blade comprises a swept blade. 
   
   
     7. A blade in accordance with  claim 1  wherein said blade comprises a wind turbine rotor blade. 
   
   
     8. A blade in accordance with  claim 1  wherein said blade comprises a plurality of third fibers resin-bonded to each other and disposed between a 25% and a 95% spanwise length of said blade, wherein said plurality of third fibers is angled at between 40° and 50° with respect to the pitch axis of said blade and comprises no more than 10% of the weight of a shell of said blade. 
   
   
     9. A wind turbine comprising a rotor having a hub and at least one blade extending outwardly from the hub, said blade comprising:
 a plurality of first fibers, wherein each of said plurality of first fibers is angled between 5° and 35° with respect to a pitch axis of said blade; and 
 a plurality of second fibers, wherein each of said plurality of second fibers is angled between 95° and 125° with respect to the pitch axis of said blade, wherein said plurality of first fibers is heavier than said plurality of second fibers, and wherein said plurality of first fibers and said plurality of second fibers are disposed to facilitate a twist of said at least one blade about the pitch axis in response to an aerodynamic bending load on said at least one blade. 
 
   
   
     10. A wind turbine in accordance with  claim 9  wherein each of said plurality of first fibers is angled between 15° and 25° with respect to the pitch axis of said blade, and each of said plurality of second fibers is angled between 105° and 115° with respect to the pitch axis of said blade. 
   
   
     11. A wind turbine in accordance with  claim 9  wherein said plurality of first fibers comprise at least one of glass fibers and carbon fibers. 
   
   
     12. A wind turbine in accordance with  claim 9  wherein said plurality of second fibers comprise at least one of glass fibers and carbon fibers. 
   
   
     13. A wind turbine in accordance with  claim 9  wherein the twist is between 2° and 15°. 
   
   
     14. A wind turbine in accordance with  claim 9  wherein said at least one blade comprises a swept blade. 
   
   
     15. A wind turbine in accordance with  claim 9  wherein said blade comprises a plurality of third fibers resin-bonded to each other, said plurality of third fibers is angled at between 40° and 50° with respect to the pitch axis of said blade and comprises no more than 10% of the weight of a shell of said blade. 
   
   
     16. A blade comprising:
 a plurality of first fibers, wherein each of said plurality of first fibers is angled between 5° and 35° with respect to a pitch axis of said blade; 
 a plurality of second fibers, wherein each of said plurality of second fibers is angled between 95° and 125° with respect to the pitch axis of said blade, said plurality of first fibers and said plurality of second fibers disposed to facilitate a twist of said blade about the pitch axis in response to an aerodynamic bending load on said blade; and 
 a plurality of third fibers resin-bonded to each other and disposed between a 25% spanwise length and a 95% spanwise length of said blade, wherein said plurality of third fibers is angled at between 40° and 50° with respect to the pitch axis of said blade and comprises no more than 10% of the weight of a shell of the blade.